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White-Coat Hypertension Matters for Outcomes

White-coat hypertension left untreated is associated with death and cardiovascular events, but out-of-office blood pressure (BP) still should be monitored in such patients, authors of a meta-analysis argued.

Across 27 observational studies with at least 3 years of follow-up, untreated white-coat hypertension carried a 36% increased risk for cardiovascular (CV) events, a 33% increased risk of all-cause mortality, and a 2.09-fold cardiovascular mortality risk; all statistically significant.

The white-coat effect among antihypertensive-treated patients held no significant risk of those outcomes, Jordana Cohen, MD, of the University of Pennsylvania in Philadelphia, and colleagues reported in the Annals of Internal Medicine.

While the 2017 national blood pressure guidelines and other recommendations have advocated out-of-office BP monitoring, real-world practice has been slow to adopt it, Cohen’s group noted.

“A major barrier is skepticism over the utility of screening for isolated office hypertension … due to unclear evidence,” they wrote.

The reason for the wildly discrepant findings in prior studies might be explained by design, as sensitivity analyses of the meta-analysis showed, Cohen’s group suggested.

White-coat hypertension only carried CV disease (CVD) risk in studies with an older mean age (at least 55) and higher risk features (chronic kidney disease, diabetes, or history of CVD). The association was also stronger in studies with longer follow-up (≥5 years).

“Therefore, the increased CVD risk associated with WCH [white coat hypertension] may be present only among older persons who have high CVD risk,” noted an accompanying editorial by Daichi Shimbo, MD of Columbia University Medical Center in New York City, and Paul Muntner, PhD, of the University of Alabama at Birmingham.

They argued that the analysis supports U.S. and European guidelines recommending out-of-office BP monitoring to screen for white-coat effects.

For adults taking antihypertensive medication, “out-of-office monitoring seems warranted to prevent intensification of antihypertensive treatment,” Shimbo and Muntner wrote. “For adults not taking antihypertensive medication … out-of-office BP monitoring is useful for distinguishing between WCH and sustained hypertension among persons with high office BP.”

About Those HTN Guidelines

A separately published comparison of blood pressure guidelines noted the agreement between the American College of Cardiology (ACC)/American Heart Association (AHA) and the European Society of Cardiology (ESC)/European Society of Hypertension (ESH) recommendations on use of home BP and ambulatory measurement.

“[T]he only real disagreement is that the ACC/AHA guidelines maintain that all people with blood pressure >130/80 mm Hg have hypertension, and blood pressure should be lowered to <130/80 mm Hg in all," George Bakris, MD, of the University of Chicago, and colleagues wrote in the Journal of the American College of Cardiology.

“In contrast, the ESC/ESH guidelines state that hypertension is defined as >140/90 mm Hg, with the goal being a level <140/90 mm Hg for all targeting to <130/80 mm Hg only in those at high cardiovascular risk, but always considering individual tolerability of the proposed goal."

The paper concluded that the difference represents no “fundamental problem” with either guideline, “rather the disconnect between a given culture’s willingness to adopt a healthy lifestyle as well as governments’ and insurance companies’ willingness to support physicians and health care providers to implement these changes.”

However, an accompanying viewpoint by Sanjay Kaul, MD, of Cedars-Sinai Medical Center in Los Angeles, wasn’t so sanguine about either guideline.

The 2017 ACC/AHA blood pressure guideline “is in reasonable compliance” with the Institute of Medicine standards; however, there’s plenty left to be desired with regard to the strength of evidence used and potential conflicts of interest, he found.

Of the total recommendations in the guideline, 35% were Class II “consistent with equivocal evidence” and 40% had level of evidence (LOE) C driven by expert opinion or limited data.

“Remarkably, 37% of ACC/AHA and 49% of ESC Class I recommendations are considered LOE: C, based principally on consensus opinion,” Kaul wrote.

While relationships with industry were nonexistent, three members of the guideline development group were on the leadership team of SPRINT, “which had an inordinate influence on the guideline recommendations” but had its own limitations, he pointed out.

Among Kaul’s list of changes that could improve the guideline process, he suggested that guideline-relevant clinical trial leaders should only serve as advisors during external peer review.

“Some may view this as an extreme position, but this is no different than what happens with external advisors at the Food and Drug Administration Advisory Committee meetings and at other federal agencies,” he wrote. “Surely, the guideline committees can find a sufficient number of individuals with required content expertise to provide unbiased input on guideline subject matter.”

Cohen disclosed support from the National Heart, Lung, and Blood Institute.

Shimbo disclosed relevant relationships with Abbott Vascular, Edward Lifesciences, Medtronic, and Tryton Medical unrelated to hypertension or blood pressure measurement.

Muntner disclosed support from Amgen.

Bakris disclosed relevant relationships with Merck, Vascular Dynamics, Bayer, and Novo Nordisk; being a member of the steering committees of CREDENCE (Janssen) and CALM-2 (Vascular Dynamics); and serving as principal investigator of the FIDELIO trial (Bayer).

Kaul disclosed no relevant relationships with industry.